If you are not able to use UNICODE, it means either your operating system or the target application does not support it. Make sure the following two conditions are satisfied.
You must be using an Operating System that supports Indian language UNICODE. See: Indian Language UNICODE Support in Windows Operating Systems. UNICODE for Devanagari scripts is officially supported only in Windows 2000 and and later operating systems. Windows 95/ Windows 98/ Windows NT don't display the Devanagari UNICODE text. Windows 2000/Windows XP uses an Open Type font "Mangal" to display Devanagari UNICODE text.
Tunga and Mangal fonts ship with the Windows XP operating system itself. If more than one UNICODE font is available for a given script, and the application permits you to choose font, then you can use the UNICODE font of your choice.
If you do not meet all above conditions then try downloading Mangal Font. to download Mangal Font. Save it on you computer and Install it using Control panel --> Font Option on Your Windows.